re: Problems with gear slop on 1997 Unisaw

That does seem like a lot of slop between the worm and gear teeth on the trunnion.  My saw is older and I have a little slop but not nearly to that degree.  As far as I know, there is no way to bring the worm closer to reduce the slop.  Is the shaft moving axially as you rotate it?  That could make a little backlash issue seem much worse.  I have noticed when adjusting the blade angle, the weight of the motor will allow me to quickly and easily move from 90° but going back to 90° is elevating the motor so it requires slightly more effort.  Your saw looks clean and with plenty of dry lube so I wouldn't imagine those conditions to be creating a problem.